TY - JOUR
T1 - The evolution of methicillin resistance in <em>Staphylococcus
aureus</em>: Similarity of genetic backgrounds in historically early
methicillin-susceptible and -resistant isolates and contemporary epidemic clones
JF - Proceedings of the National Academy of Sciences
JO - Proc Natl Acad Sci USA
SP - 9865
LP - 9870
DO - 10.1073/pnas.161272898
VL - 98
IS - 17
AU - Crisóstomo, M. Inês
AU - Westh, Henrik
AU - Tomasz, Alexander
AU - Chung, Marilyn
AU - Oliveira, Duarte C.
AU - de Lencastre, Hermínia
Y1 - 2001/08/14
UR - http://www.pnas.org/content/98/17/9865.abstract
N2 - The key genetic component of methicillin resistance, the mecA determinant, is not native to Staphylococcus aureus. Thus, the evolution of methicillin-resistant S. aureus (MRSA) must have begun with the acquisition of the mecA determinant from an unknown heterologous source some time before the first reported appearance of MRSA isolates in clinical specimens in the U.K. and Denmark (in the early 1960s). We compared the genetic backgrounds and phenotypes of a group of methicillin-susceptible S. aureus (MSSA) isolates to the properties of MRSA strains isolated in Denmark and the U.K. during the same time period, and also to the genetic profiles of contemporary epidemic clones of MRSA. All early MRSA isolates resembled a large group of the early MSSA blood isolates in phenotypic and genetic properties, including phage group, antibiotype (resistance to penicillin, streptomycin, and tetracycline), pulsed-field gel electrophoresis pattern, and spaA type and multilocus sequence type, strongly suggesting that the early MSSA examined here represented the progeny of a strain that served as one of the first S. aureus recipients of the methicillin-resistance determinant in Europe. The genetic background of this group of early MSSA isolates was also very similar to that of the widely disseminated contemporary “Iberian clone” of MRSA, suggesting that genetic determinants present in early MSSA and essential for some aspects of the epidemicity and/or virulence of these strains may have been retained by this highly successful contemporary MRSA lineage. M,methicillin;P,penicillin;S,streptomycin;T,tetracycline;E,erythromycin;MRSA,M-resistant S. aureus;MSSA,M-susceptible S. aureus;PFGE,pulsed-field gel electrophoresis;MLST,multilocus sequence typing
ER -